1968 Firebird, Pontiac 350, 4 speed, no AC.
Pertronix Ignitor 3 dizzy - seems to be part # D7120700
Prior owner purchased in 2012

Issue: All is well, idle ~ 650 in neutral at a stop. Without warning, rpm drops to ~ 400.
I need to goose the gas to ~ 1100-1200 to keep it running.
Just as fast all goes back to normal.

Last fall, put a timing light on it. Loosen dizzy to set timing. Don't recall exacts, but was running good.
Tighten dizzy while car was running and it started to stumble. Thought I'd moved dizzy. Timing light was
non functional, no strobe. Timing light wires were good, not in the way. Press trigger again, light works
and stumble is gone. This continued, off and on, for some time before I gave up.

Took it to a local trusted mechanic. He had same results. Put a spark tester on #1, Intermittent no spark.
R&R plugs, wires, coil - issue still exists. He claimed, when issue arises, there is less than 12v to the coil.
At this point, drove it home w/no issue. Packed it away for winter.

Yesterday, started to dig into wiring. The more I dig, the more old wires I find. I think I might be better off
running new, but got minimal clue on right way to do it. Based on past posts here, I should not use existing
wires and fuse box.

Any tips/tricks would be appreciated.

Thanks much,
.....don t. .....